path: root/arch/s390/kvm/kvm-s390.c
diff options
authorChristian Borntraeger <borntraeger@de.ibm.com>2008-05-07 09:22:53 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-05-07 09:23:01 +0200
commit0eaeafa10f3b2bd027e95859a6785d4c7fcc174c (patch)
tree97676107c28393326944bd3d922e7eeaa5caf942 /arch/s390/kvm/kvm-s390.c
parent2688905e6a9b3647bf7b452cb0ff2bdb166bd8fe (diff)
[S390] s390-kvm: leave sie context on work. Removes preemption requirement
From: Martin Schwidefsky <schwidefsky@de.ibm.com> This patch fixes a bug with cpu bound guest on kvm-s390. Sometimes it was impossible to deliver a signal to a spinning guest. We used preemption as a circumvention. The preemption notifiers called vcpu_load, which checked for pending signals and triggered a host intercept. But even with preemption, a sigkill was not delivered immediately. This patch changes the low level host interrupt handler to check for the SIE instruction, if TIF_WORK is set. In that case we change the instruction pointer of the return PSW to rerun the vcpu_run loop. The kvm code sees an intercept reason 0 if that happens. This patch adds accounting for these types of intercept as well. The advantages: - works with and without preemption - signals are delivered immediately - much better host latencies without preemption Acked-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 98d1e73e01f..0ac36a649eb 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -31,6 +31,7 @@
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "userspace_handled", VCPU_STAT(exit_userspace) },
+ { "exit_null", VCPU_STAT(exit_null) },
{ "exit_validity", VCPU_STAT(exit_validity) },
{ "exit_stop_request", VCPU_STAT(exit_stop_request) },
{ "exit_external_request", VCPU_STAT(exit_external_request) },
@@ -221,10 +222,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
vcpu->arch.guest_fpregs.fpc &= FPC_VALID_MASK;
- if (signal_pending(current))
- atomic_set_mask(CPUSTAT_STOP_INT,
- &vcpu->arch.sie_block->cpuflags);
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)